Above- and belowground responses to tree thinning depend on the treatment of tree debris

Effects of fuels reductions on plant communities and soils in a Piñon-juniper woodland

“…Along with reducing risk of high severity fires, the legislation includes the explicit goal of restoring forest ecosystems by decreasing fuel loads in a manner that maintains ecological integrity and promotes a return to historic fire cycles (HFRA, 2003). Within the context of maintaining ecological integrity, however, the effects of fuels-reduction treatments on plant communities and soil processes are not well documented (Boerner et al, 2009), especially in the semi-arid woodland environments of the western U.S. (Brockway et al, 2002;Owen et al, 2009).…”

“…BSCs play an important role in soil nutrient dynamics of these nutrient poor systems (Evans and Ehleringer, 1993;Evans and Johansen, 1999). However, BSCs are highly susceptible to soil surface disturbance (Barger et al, 2006;Belnap and Lange, 2002;Mack and Thompson, 1982) and the suite of fuels-reduction treatments applied to Piñon-juniper woodlands may have direct, negative effects on BSC communities caused by the use of prescribed fire (Owen et al, 2009) and soil surface disturbance related to foot-traffic and heavy machinery (Belnap and Gillette, 1998).…”

“…Possible benefits from fuels reduction include increased understory plant cover (Owen et al, 2009;Brockway et al, 2002), increased plant diversity (Brockway et al, 2002), decreased soil erosion (Hastings et al, 2003), and increased soil moisture (Owen et al, 2009;Miller and Seastedt, 2009). Risks may include changes in plant community composition (Miller and Seastedt, 2009;Wolk and Rocca, 2009), increases in invasive species specifically Bromus tectorum (Owen et al, 2009;Wolk and Rocca, 2009), and increased soil erosion (Barger, unpublished data). Different treatment types may differ in their effects on the balance between risks and benefits associated with fuels reduction.…”

Surface fuel loadings within mulching treatments in Colorado coniferous forests

“…These techniques (hereafter referred to as mulching) should reduce active crown fire risk by redistributing the canopy and ladder fuels and compacting them on the forest floor. Mulching treatments are being applied in a variety of forest types across the western U.S. (Hood and Wu, 2006;Kane et al, 2009;Owen et al, 2009;Reiner et al, 2009;Wolk and Rocca, 2009;Sharik et al, 2010), however; there is limited data on how these treatments alter surface fuel characteristics and in turn potential fire behavior.…”

Cheatgrass Invasion - The Below-Ground Connection

“…The idea behind these applications is that added carbon immobilizes nitrogen in soil bacteria by increasing the C/N ratio (Perry et al, 2010). This approach, though, has not always been successful in long-term restoration of native or non-native perennials and studies using woodchips from masticated pinyon-juniper woodland even resulted in increased B. tectorum cover (Mazzola et al, 2008;Owen et al 2009). The timing of carbon applications is crucial since nitrogen accumulated in soil microbes can be released by freeze-thaw or wet-dry cycles resulting in nutrient flushes that, if superimposed on cheatgrass active growth periods, could foster the growth of this invasive instead of decreasing it.…”